Archaea

You may remember from class that one of the three domains of life is the Archaea (the other two are Bacteria and Eukarya). Members of Archaea are prokaryotic organisms that are usually found in extreme environments - in fact they are often called 'extremophiles'. They are found in areas of high salinity, temperature, acidity, or alkilinity. Others are found where oxygen levels are extremely low or non-existant (anoxic environments). Some very cool and very different biology going on with them (but not THAT different, which makes them even more interesting). Here are a few websites if you are interested in learning more about them:

Triumph of the archaea (an older article by Carl Zimmer, an exceptional science writer)

Intro to the Archaea

WikiPedia article on Archaea

Some biologists think that the Archaea are the base of the tree of life - that the earliest living things were Archaea (or Archaea-like) and that all other living things evolved from them. Recently there has been some debate over this sentiment as DNA evidence has come out to suggest that this may not be the case. Biology is full of mysteries and unsolved puzzles and the Archaea are one of them.